Just over two thirds (68.8%) of entries scored A*-C, up 0.7 percentage points on last summer, according to statistics published by the Joint Council for Qualifications (JCQ).

But the overall A*-G pass rate has fallen for the second year running, and is down 0.3 percentage points to 98.5% from 98.8% in 2013.

The proportion of entries awarded the highest grade has also fallen slightly, with 6.7% gaining an A*, down from 6.8% last year.

It is the third year in a row that this has dropped.

The rise in A*-C grades is the first increase in three years, and comes despite massive differences in this year’s English and maths results, both of which are considered key subjects.

In total, 61.7% of English entries scored a C or higher this year, down 1.9 percentage points from last summer.

This is believed to be the biggest drop in the qualification’s history.

Maths saw an opposite result, with 62.4% of entries gaining an A*-C grade, up a massive 4.8 percentage points on 2013.

Exam chiefs suggested that there were several reasons for the hike in maths results, including a decision that in England, only a teenager’s first attempt at an exam would count in school league tables.

This may have meant that fewer lower-performing 15-year-olds are taking maths GCSE early, and bright students, who may have taken the qualification early in the past, are now sitting it in the summer, JCQ said.

In recent years there had been a growing trend towards schools entering pupils for exams early, or multiple times, but the new rule has changed this, and figures published earlier this year showed around a 40% drop in early entry across all subjects.

JCQ also said that the fall in English grades could be down to strong candidates taking advantage of a final opportunity to sit the exam last winter, and a switch by students to take an International GCSE (IGCSE) in the subject.